Catalyst and method of preparing the same



UNITED STATES PATENT- orrlca.

JOHN coLLms cLANcY, or PROVIDENCE, nnonn isnarrn assmnon TO THE mrnocmr CORPORATION, or rnov'mmwcrz, nnpnn ISLAND, A .conronarron or nnonn ISLAND.

CATALYST AND METHOD OF PREPARING THE SAME.

No Drawing.

- To all whom it may concern:

Be it known that I, JOHN COLLINS CLANoY, a subject of the Kingof Great Britain, residing at Providence, in the county of Providence andState of Rhode' Island, have invented certain new and useful Improvements in Catalysts and Methods of Preparing the Same, of which the following is a specification.

This invention comprises, as a new article of manufacture, a metal of the type including silver and copper, in a highly expanded and porous but coherent form; and the method by which the saidproduct may be prepared. The metals or metallic residues obtained in accordance with this invention are highly active catalysts, and are useful in connection with numerous reactions, including for example the preferential combustion of carbon m'onoxid in presence of hydrogen. by reaction with steam; the formation of nitrogen oxi'ds by oxidation ofammonia in presence of air; the preparation of formaldehyde by limited oxidation of methyl alcohol or methane, etc.

According to my invention silver or copper cyanamid, or a mixture of these salts,

'isfirst prepared, preferably in the wet way and in accordance with the now known methods, by precipitating a dissolved cyanamid by the appropriate metal salt or salts,

such for example as silver nitrate, cupric chlorid, or mixtures thereof. The resulting precipitate, which is yellow in the caseof silver cyanamid or black in the case of c'op plied to other purposes for which very per cyanamid, is washed and dried and thereafter heated under oxidizing conditions to the decomposing temperature.

I have found that these salts when moderately heated, say to'250--350 C., in presing highly expanded product appears to consist largely or entirely of a metallic residue which is extremely lightand porous,

- is readily traversed by gases, but is never-- theless sufiiciently coherent to permit its employment as a catalyst for various gas reactions without the necessity of associating it with a pumice or other inert support of filler; although such extraneous mixtures may of course be used if, desired.- The resi- Specification of Letters Patent, Patented Aug. 15, 1922; Application filed Hay 8, 192i). Serial No. 380,002.

dues derived from silver and copper cyanamlds may be used individually, but I prefer 'as a? rule to employ mixtures of the two,

either in approximately equal or in molecular proportions, since I have found that thereby a product of increased catalytic acother materials, such for example as the metal-cyanogen complexes mentioned below, into small cubes, pellets or other approa crucible and heating them in presence of air to the point where the sudden expansion or pufiing occurs. By proceeding in this way I have produced ag 'regates which are apparently metallic in character and have an apparent specific gravity-of the order of {LS-for Cu and 5.8 for Ag residues.

" As stated above, these expanded products are highly active catalysts for many reactions, although they may of course be apfinely subdivided metals or metallic aggregates are desired.

For certain catalytic purposes, as for example for the oxidation of ammonia, I prefer to incorporate ,with these catalysts, comprising either the silver or the copper residue or any mixtures thereof, relatively small proportions of certain cyanogen complexes which have the effect of materially enhancing the catalytic activity, and arehereinafter for simplicity designated activating agents. The cyanogen complexes referred to are metal derivatives of the ferroand ferri-cyanides, such for example as bismuth ferroand ferri-cyanide; calcium cerium ferro-cyanide; cerium cobalt ferro-cyanide; vanadium ferro-c'yanide; molybdenum ferro-cyanide; or the like. These complexes, when heated to moderate temperatures under oxidizing conditions are likewise conpriate shapes; and then charging them into all metals of the type of silver and copper.

The expression metal of the typeof silver and copper is employed to desi hate all metals, the cyanamids of which,'l1ke silver and copper, decompose upon the application of heat with the" formation of porous catalytic metallic residues.

I claim V 1. As a new article of manufacture, a catalyticall active body com rising the product 0 thermal decomposition under oxidizing conditions of the cyanamids of a plurality of metals of the type of silver and copper.

- 2. As a catalyticall new article f manufacture,- 9. active .bo y comprising the product 0 thermal decomposition under oxidizin conditions of a mixture of the cyanami s of silver and copper.

3. As a new article of manufacture, a.

catalyticall active body comprising the product 0 thermal decomposition under oxidizin conditions offa cyanamid of a metal 0 the type of'silver and cop er.

4. As a new article of manu acture, a catalyticall active body comprising the product 0 thermal decomposition under oxidizing conditions of a mixture of cyanamids of metals of the type of silver and copper in proportions corresponding to their molecular weights.

5. As a new article of manufacture, a

catalytically active body comprising the product of thermal decomposition under oxidizing conditions of a'mixture of the cyanamids of silver and copper in proportions corresponding to their molecular weights.

6. As a new article of manufacture, a catalyticall active body comprisin :the product 0 thermal decomposition 'under oxidiz-in conditions of a cyanamid." of a metal 0 the type of silver and copper in associationwithan activating agent.

7. As a new article of manufacture, a catalyticall active body comprising the product o thermal decompos tion under oxidizing conditions of a mixture of cyanamids of metals of the type of silver and copper in association with an activating agent.

8. As a new article of manufacture, a catalyticall active body comprising the product 0 thermal decomposition under [oxidizing conditions of a cganamid of a metal of the type of silver an copper irrassociation with an activating agent compris- 'ing a decomposition product of a metalcyanogen complex.

9. As a new article of manufacture, a catalytically' active body comprising the :product of thermal decomposition ,under oxidizing conditions of a mixture of cyanamids of metals of the type of silver and copper in association with an activating agent comprising a decomposition product of a metal-cyanogen.complex.

10. As a new article of manufacture, a

highly expanded product comprising a metal of the type of silver and copper, in association with an activating agent.

11. As a new article of manufacture a highly expanded product comprising a mixture of metals of the type of silver and copper, in association with an activating agent.

12. As a new article of manufacture, a

highly expanded p'roduct comprising a metal of the type of silver and copper, in associa- .tion with an activating agent comprising a decomposition product of a metal-cyanogen complex.

13. As new article of. manufacture, a

highly expanded product comprising a mlxture of metals of the type ofisllver and copper, in association w'ithzan activating agent comprising a decomposition product of a metal-cyanogen'complex. r

14. As a new article of manufacture, .a highly expanded coherent product comprising a metal of the type of silver and copper, said product having the essential characteristics of the product of thermal decomposition of a metallic cyanamid under oxidizing conditions.

15. As a new article of manufacture, a

highly expanded coherent product comprising a mixture of metals of the type of silver and copper, said product having the essential'characteristics of the product of thermal decomposition of a metallic cyanamid.

16. Method of preparing a product having catalytic activity, comprising sub'ecting a c anamid of a metal of the type 0 silver an copper to thermal decomposltion under oxidizing conditions. 7

17. Method of preparing a product having catalytic activity, comprising subg'ecting a cyanamid of a metal ofithe type 0 gen complex, to thermal decomposition un der oxidizing conditions.

18. Method of preparing a product having catalytic activity, comprising subjecting a mixture. of cyanamids of metal of the type of silver and co per, associated with a metal cyanogen comp ex, to thermal decomposi t1on under. oxidizing conditions. I 1

In testimony whereof, I afiix my signature.

JOHN COLLINS CLANCY.

silver and copper, associated with a metal-cyano 

